The use of leather substrates in car interiors and in furniture has increased significantly in recent years. Especially light coloured, beige or white leather car interior or furniture has found increased importance for its attractive appearance. A coating is typically applied to the surface of the leather to provide increased protection. Such leather substrates are commonly known as coated or finished leather to distinguish them from leather substrates that do not contain such protective coatings and which are commonly referred to as un-finished leather, suede or nubuck leather. Protective coatings may comprise several layers, including at least one first layer, also referred to as base coat or primer layer. The coatings may further comprise middle coats and topcoats. To make leather substrates stain and dirt repellent topcoats comprising fluorine-containing resins have been used, as is described, for example, in European patent applications No. EP 1 123 981 and EP 1 577 400. EP 1123981 discloses leather coated with a cured fluorine-containing resin coating. The coating is obtained by curing a curable fluorine-containing resin composition comprising a fluorine-containing resin having a reactive curable group and a curing agent. EP 1 577 400 describes a paint composition for leather comprising a fluorine-containing resin and a silicone oil, and a paint composition for leather comprising a curable fluorine-containing resin, a curing agent and a silicone oil.
Despite developments made in protective top coats for finished leathers, these leathers may still suffer from dry soils and aqueous or oily soils that attach to the coating and soil removal may still be difficult. A further disadvantage is that in order to be effective in repellency, in particular for stain repellency and stain release, fluorine-containing top layers have to be highly cross-linked and of considerable thickness. This, however, may lead to give the leather an unnatural glossy appearance, which may be undesired.
A further disadvantage of thick coatings lies in potential crack formation when bending the leather substrate. This is of particular importance for leather substrates, used in articles having an outer surface that needs to be flexible in its use, such as for example seats, garments, shoes, handbags, gloves and belts.
Therefore, there has been a continuous need for coating compositions that may provide good or improved stain and/or soil resistance to leather substrates. Desirably, such coatings obtained from such compositions maintain the natural look or mat appearance of the leather. Favourably, the compositions provide a flexible coating that has no or only reduced crack formation upon bending.